title: Normal morphology of sacroiliac joints in children: magnetic resonance studies related to age and sex.
abstract: OBJECTIVE
  To determine in a prospective study the normal MRI morphology of the sacroiliac joints (SIJs) in relation to age and sex during adolescence.
  
  
  METHODS
  A total of 98 children (63 boys, mean age 12.7 +/- 2.8 years; 35 girls, mean age 13.7 +/- 2.3 years), ranging in age from 8 to 17 years, with juvenile chronic arthritis (JCA) but without signs of sacroiliitis fulfilled the study prerequisites (no back pain and no pathologic changes of the SIJs on physical examination before MRI in a 1.5-year follow-up). An additional eight HLA-B27-negative boys and eight HLA-B27-negative girls without arthritis served as controls. The MRI protocol comprised a T1-weighted SE sequence, an opposed-phase T2*-weighted GE sequence, and a dynamic contrast-enhanced study in single-section technique.
  
  
  RESULTS
  Noncontrast MRI permitted differentiation of "open" from ossified segmental and lateral apophyses of the sacral wings, with a significant difference in age (P < 0.05) between children with open and ossified apophyses. Ossification of the apophyses of the sacral wings was seen significantly earlier (P < 0.05) in girls than in boys. Girls also had a significantly higher incidence of transitional lumbosacral vertebrae, pelvic asymmetries, and accessory joints. In the contrast-enhanced opposed-phase MRI study, normal cartilage of the SIJs showed no contrast enhancement whereas the joint capsule showed a moderate enhancement.
  
  
  CONCLUSIONS
  There are significant age- and sex-related differences in the normal MRI morphology of juvenile SIJs. Our findings might serve as a standard of comparison for the evaluation of pathologic changes--in particular for the early identification of juvenile sacroiliitis.
authors.affiliation: Institut für Röntgendiagnostik, Charité, Humboldt-Universität zu Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Bollow
authors.forename: J
authors.initials: J
authors.lastname: Braun
authors.forename: J
authors.initials: J
authors.lastname: Kannenberg
authors.forename: T
authors.initials: T
authors.lastname: Biedermann
authors.forename: C
authors.initials: C
authors.lastname: Schauer-Petrowskaja
authors.forename: S
authors.initials: S
authors.lastname: Paris
authors.forename: S
authors.initials: S
authors.lastname: Mutze
authors.forename: B
authors.initials: B
authors.lastname: Hamm
mesh_terms: D000293:Adolescent; D000375:Aging; D001171:Arthritis, Juvenile / Q000150:complications; D002358:Cartilage, Articular / Q000033:anatomy & histology; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D015796:HLA-B27 Antigen / Q000032:analysis; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D012446:Sacroiliac Joint / Q000033:anatomy & histology*; D012727:Sex Characteristics
chemical_list: D015796:HLA-B27 Antigen